Package of reversible thermoplastic impression composition



NW; 7, m L. E. HARRQSON 2.17.663

PACKAGE OF REVERSIBLE THERMOPLASTIC IMPRESSION COMPOSITION Filed July 24, 1936 a INVENTOR. laarfiiaceEflizrr wow BYMM 4 fluent by heating, cooling the fluent material un- Patented Nov. 7, 1939 PACKAGE OF REVERSIBLE THERMO- PLASTIC HVIPRESSION COMPOSITION Laurence E.-Harrison, Altadena, Calif., assignor, by mesne assignments, to Surgident, Ltd., Los Angeles, Calif., a corporation of California Application July 24, 1936, Serial No. 92,463

4 Claims.

application is a continuation-in-part of my-application SerialNo. 1,744, filed January 14, 1935,'and relates toan advantageous package in which a reversible-thermoplastic dental impres- :sioncomposition may be packaged and marketed.

The principal object of the invention is to provide a package which may be easily and cheaply prepared and which will preserve the material in der conditions of agitation or other physical manipulations until a temperature low enough for insertion into the mouth of a patient isobtained, after which the material is placed in a suitable tray or the like and an impression obtained of the desired portion of the patients mouth, the impression being cooled in place to a relatively rigid state and subsequently, withdrawn from the mouth and employed in the production of plaster casts or other reproductions. Certain of these compositions comprise a base material of a hydrocolloid nature such as. agar-agar or glue, together with certain modifying agents contribut ing to the properties of the material both in the relatively rigid state. One type fluent and the described in the U. S. patent to of material is Poller No. 1,672,776, and other compositions are package,-but are preferably preserved against contamination by contact with human hands or other detrimental agencies, so that the material may be introduced into the patients mouth 'in a sterile condition. In such compositions as are of a hydrocolloid nature or contain any significant proportions of hydrocolloid material, it is necessary that the package provide adequate hermetic conditions whereby no significant moisture loss is experienced by the material during storage conditions. Such hydrocolloid materials have been conventionally enclosed in atin-foil wrapper or the like, without sealing, and since such apackage heated exteriorly to raise the material to the desired temperature and in which a kneading or mixing of the material may be obtained to thoroughly homogenize the same.

According to the present invention a substantially continuous envelope of flexible material is provided for a body of the impression material,

air as well as from contact by human hands or other agencies, and serves as a suitable container for the impression material during heating and kneadingpreparatory for use, and in its preferred embodiment also protects the material against moisture loss during storage.

The accompanying drawing illustrates two embodiments of the invention, and referring there- Fig. 1 is a partly broken-away side view of one embodiment of v the invention, which may be formed by a clipping procedure; and i Fig. 2 is a partly broken-away view of an alternative embodiment, which may be formed from preformed tubular envelope material.

As a specific example of'a reversible hydrocolloid impression material to which the present invention is adapted, I may take from 140 to 200 grams of an oleaginous material such as resin oil to which is added approximately one-half per cent of a suitable emulsifying agent such as triethanolamine, heat the mixture to about 100 C. and emulsify the same with approximately 90 grams of water. To the above emulsified mixture I may add'from 100 to200 grams of a balatalike thermoplastic substance such as guttapercha, balata, or a balata-like rubber isomer such as described in Industrial and Engineering Chemistry, vol. 19, pages 1325 and 1333, December, 1927, preferably in the form of a 25% solution in benzol or other suitable solvent. This thermoplastic material emulsifies in the above (mixture and is homogeneously distributed therethrough under agitation, the material being kept hot to drive off the solvent. Following the emulsification of the above materials I may add approximately 2000 grams of an aqueous solution of a reversible hydrocolloid such as agar-agar, for -example, 150 grams of agar-agar dissolved in 1900 grams of water. The hydrocolloid material is preferably added hot, and upon agitation will emulsify in the above mixture to form a homogeneous mass. To the above mixture approximately 300 grams of wax may be added, for example, a mixture of waxes containing four parts ceresln and one part candelilla, in melted condition, whichwax also emulsifies in the mixture. Suitable amounts ofdesirable flavoring, s'centing, and/o; coloring material may be added to the finished mixture and the same may be cooled to a semi-plastic state and extruded through a die to form bodies of the material of cylindrical or other which adequately protects the material from the v desired shape and of the proper size, which upon cooling to their relatively rigid or solid state are ready for packaging.

A body of reversible hydrocolloid impression material, formed into cylindrical or any other suitable shape by molding or otherwise, may ac-' cording to this invention be dipped in a solution of a suitable cellulose compound adapted to form, upon evaporation of the solvent, 9. continuous coating of suitable thickness over the surface of the molded body. For this purpose, I may use, for example, a solution of Celluloid or cellulose acetate composition in ethyl acetate, of suitable concentration, and the dipping may be carried out by inserting a wire into the molded body I, as shown in Fig. 1, at some such location as is indicated by the dash line A, dipping the same by means of said wire into said solution; removing the. same therefrom, allowing the coating to partially dryand thus forming a tubular container or envelope 2, removing the wire, and then applying a small quantity of the same or equivalent solution to the opening through which the wire was drawn as at 3, and

allowing the entire coating to thoroughly dry.

of rubber or comparable material, suitably sealing the ends of the envelope, which may be 9.1-,

lowed to project beyond the ends of the stick a short distance, by means of a wrap of wire 8' or the like to bring the envelope ends into close compressive engagement so that an effective fluid-tight seal is produced by the envelope material itself. If the ends of the'rubber envelope are securely brought into engagement and held in such conditionv by an adequate wrap of such,

-Jacent body temperature-or at least to a temperature such that the material maybe-comfortably inserted within the patients mouth. The use of an envelope or package of flexible material per,-

mits adequate kneading of the heated impression material within said envelope, to homogenize the'impression material and prepare the same for use. The envelope may then be opened by slitting the same at one end or cutting one end of the envelope off with a pair of shears or the like, and the composition may then be extruded, by squeezing the envelope, into the customary type of dental impression tray employed by dental practitioners. This tray is then insertedinto the patients mouth and the desired impression secured.

It will beapparent that the first described form of package is not entirely adequate of itself to prevent escape of moisture under storage conditions, and it may be necessary to enclose 9.

plurality of such packages a suitable hermetically sealed can or the like after the manner of the tin-foil wrapped packages above described.

v This type of package is, however, clearly adapted to the above described method of homogenizing the material in fluent condition for use and extruding the material from the envelope. The rubber envelope type of package immediately above described is adequate to prevent moisture change in the contained material under any conditions, and even though a body of material has been placed in the desired fluent condition ready for use by the dental practitioner, if it should develop that the patient does not keep his appointment and the-material is not to be used,

. ible thermoplastic materials described in the several above-mentioned patents are clearly useful therein. Other flexible coating materials than rubber or Celluloid will also occur to one skilled in'the art as being useful in the formation of the package, using either a preformed container or a container formed by a dipping procedure, or any other suitable means for packaging the impression material in the container. It will also be apparent that the rubber package is not necessarily sealed by a wire wrap as specifically above described, inasmuch as cementlike agencies may be employed for that purpose.

I therefore do not consider myself 'limited to the specific elements and conceptions herein setforth but rather to the scope of the appended claims. The term flexible as used herein will be understood to designate a material which is sumciently capable of plastic or resilient deformation at temperatures within the kneading range to.permit the kneading operation to be carried out. Furthermore, it will be appreciated that the envelope material is preferably nonmetallic in nature, inasmuch as a flexible envelope of metal would necessarily be relatively thin-walled, and would thus be subject to rupture in the kneading operation.

I claim:

l. A package of reversible thermoplastic im pression composition which comprises a stick of such composition and a container of flexible nonmetallic material enclosing said stik and providing an air-tight enevelope therefor.

2. A package of reversible.thermoplastic impression composition which comprises a stick of such composition and a containerof flexible nonmetallic material enclosingv said stick and proyiding an air-tight and moisture-impervious envelope therefor.

3. A hermetic package of reversible thermoplastic impression composition which comprises a stick of such composition and an envelope of flexible rubber completely enclosing said stick.

4. A hermetic package of moisture-containing ,hydrociolloid impressioncomposition which com- 

